Apparatus for braking and overlapping of sheets made of paper or the like to be deposited on a stack

ABSTRACT

An apparatus for braking the advance of and effecting overlapping of sheets of paper, cardboard or the like material that are to be deposited on a stack in which advancing sheets are fed over a suction brake installation including a suction box having a perforated top through which a periodically applied suction is effected and a perforated control belt means movably arranged over the perforated top of the suction box or chamber to align the perforations of the control belt means with the perforations in the top of the suction box or chamber by moving the control belt means in accordance with the rythm of the fed sheet sequence.

0 United States Patent [151 3,659,839 Bau k 1 May 2, 1972 54] APPARATUS FOR BRAKING AND 2,l65,l72 7/1939 Backhouse .271/59 OVERLAPPING 0F SHEETS MADE OF 3,l90,644 6/1965 Schwebel 271m p p OR H LIKE o BE 2,087,997 7/!937 Reinartz ..271/4s x DEPOSITED ON A STACK 1,728,329 9/l929 Broadmeyer v271M) [72] Inventor: Horst Baucke, Solingen-Ohligs, Germany 4 Primary Examiner-Joseph Wegbrert [73] Assignee: Jagenberg-Werke AG, Dusseldorf, Ger- Anomey Burgess Dinidage & Sprung many [22] Filed: Mar. 27, 1970 [57] ABSTRACT [2]] Appl' 23420 An apparatus for braking the advance of and effecting overlapping of sheets of paper. cardboard or the like material that [30] Foreign Application Priority Data are to be deposited on a stack in which advancing sheets are fed over a suction brake installation including a suction box Germany 19 616") having a perforated top through which a periodically applied [52] Us C" "Zn/46 271/78 suction is effected and a perforated control belt means 5| 1 Int 0 I l g I I Q u I 56gb 29/68 movably arranged over the perforated top of the suction box [53] n w f Search 27 53 59 9 74 77 or chamber to align the perforations of the control belt means 271/78 with the perforations in the top of the suction box or chamber by moving the control belt means in accordance with the [56] References Cited rythm of the fed sheet sequence.

UNITED STATES PATENTS 5 Claims, 7 Drawing Figures 3,432.16] 3/1969 Dale et al ..27l/46 Patented May 2, 1972 3 Sheets-Sheet 1 Patented May 2, 1972 3,659,839 7 3 Sheets-Sheet 2 Fig. 3

Patented May 2, 1972 3,659,839

3 Sheets-Sheet 3 Fig.4

Fig. 5

APPARATUS FOR BRAKING AND OVERLAPPING OF SHEETS MADE OF PAPER OR THE LIKE TO BE DEPOSITED ON A STACK BACKGROUND OF THE INVENTION The present invention relates to apparatus for braking and overlapping of sheets made of paper, cardboard or the like material to be deposited upon a stack, said sheets being ejected from sheet-producing machines, for example, transverse or cross.

In machines of this type, especially in transverse cutters, which cut the paper, cardboard or the like which unwind from the supply roll into determined sheet sizes, it is necessary to brake the sheets leaving the transverse cutting zone at high speed so as to enable orderly and disturbance-free stacking of the sheets.

The braking is done is such manner in known fashion that the sheets leaving the transverse cutter apparatus first are accelerated until they reach a spatial distance between the individual sheets, and that thereafter they are delayed again in such manner that a slow and disturbance-free stacking of the sheets can take place.

For this reason, the deposit speed must be substantially less than the ejection speed of the machine, or in other words the sheets must be brought to overlap, with the extent of overlapping being determined by the advancing speed of the conveyor belts. In this manner, the reduction of the advancing speed of the sheets takes place such that several conveyor installations are arranged successively of which each successive one operates at a lower speed than the immediately preceding one.

In order to initiate overlapping, one uses in known manner preferably suction air which, relative to the direction of movement of the sheet, exerts a braking effect on the rearward end with the result that the forward area of the following sheet slides over the rear area of the preceding sheet and thus initiates overlapping. In this manner, the effective upper side of the suction brake device is positioned somewhat lower than the preceding conveyor belt section so that by virtue of this slight difference in height, a disturbance-free overlapping is ensured. In this type of operation, the limitation of the braking effect upon the rearward sheet end is of particular significance since, as a result thereof, the sheet is stretched, likewise avoiding crumbling or bulging of the sheet which would otherwise occur if a braking effect is exerted upon the end of the sheet which is disposed forwardly as regards the direction of advance.

With high operating speeds and particularly when then papers are processed, it is therefore indispensable for the purpose of avoiding disturbances that precautions are met which ensure that the suction braking is exerted rhythmically upon the rearward end of the sheet in dependency upon the sequence of sheets. In other words, it is necessary to avoid that the braking effect is exened without interruption.

These obstacles appear in known installations, comprising a suction box and one or several endless suction belts guided around said suction box. Especially in that situation where there is rapid sequence of sheets, this type of embodiment by virtue of the large suction box volume and output volume does not provide the required quick establishment and release of a vacuum.

In order to perform a braking effect taking place in the rhythm of the sheet sequence, it has further been proposed to utilize a suction brake installation comprising a stationary split suction tube, a rotary and likewise slit control tube and a perforated jacket with a porous conveyor belt enclosing said control tube. The drawback of this type of embodiment must be seen in the high expenditure for material and work since the individual tubes must be enclosed so as to fit tightly in order to prevent slot losses. Moreover, there appear significant inertia moments by virtue of the masses being in motion, said inertia moments adversely influencing the controllability of such an installation.

SUMMARY OF THE INVENTION Accordingly, the present invention has for an object to provide a suction brake installation which is characterized by low expenditure, achieving a periodic braking effect and which, whem compared with the known types of embodiments moreover possesses the advantage of being quickly and easily controllable.

In order to solve this object, it is now inventively proposed, with the use of an installation for braking and overlapping sheets to be deposited upon a stack, the rearward ends of such sheets coming into the area of a periodically operating suction brake installation, to align the perforations of the suction chamber covered by a perforated control belt with the perforations of said control belt by virtue of the movement of the control belt and the rhythm of the sheet sequence.

The arrangement is such that the perforated control belt is movable guided between the perforated suction chamber and a perforated cover plate so as to coincide with such suction chamber. In this mode, the movable control belt can be an endlessly revolving perforate belt, or the movable control belt can be formed by a perforate belt reciprocating in rhythm with the sheet sequence.

A further characteristic of the inventive installation is that the movements of the perforate belt are controlled in dependency upon the sheet sequence. This measure assures that, independent of the advancing speed of the sheets and independent of their format, the suction air acts upon a sheet rhythmically only in the rear zone of said sheet.

Practical experiments and measurements have shown that the sub-atmospheric pressure available in the zone of of the suction location reduces with increasing machine speed so that with unchanged suction output and increasing machine speed, the sheet is braked insufficiently since, in addition thereto, the kinetic energy of the sheet increases proportionally to the square of the machine speed. This results in irregularities in overlapping by virtue of the insufficient braking effect which can lead to disturbances in the stacking process. Thus, in order to obviate these obstacles one must take precautions which assure that the suction output is increased with increasing machine speed. One way to accomplish this is that the efi'ective through-flow cross-section of the perforations of the suction brake installation is adjusted to the machine speed, that is to say that the cross-sections are enlarged with increasing speed. The change of the through-flow cross-section can be achieved such that the aligned parts of the suction brake installation are displaced laterally. Another way is provided by a likewise perforated adjustable slide member which is adjustably disposed between the suction chamber and the cover plate.

An advantage by virtue of the arrangement is presented when the movements of the control belt are directed essentially perpendicularly in relation to the conveyor installation of the sheets. This type of arrangement permits a narrow construction of the suction chamber which extends over the width of the sheet path, thus giving improved assembly possibility with small space requirements.

BRIEF DESCRIPTION OF THE DRAWINGS Further and more specific objects and advantages of the present invention will be readily apparent from the following description taken in connection with the accompanying drawings in which:

FIG. 1 shows in schematic representation a side elevational view of a suction brake installation built into a conveyor installation',

FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. 1;

FIG. 3 is a perspective view of the suction brake installation;

FIGS. 4 to 6 are enlarged fragmentary cross-sectional views through the suction perforations illustrating various phases of the suction process; and

FIG. 7 is a fragmentary cross-sectional view of DETAILED DESCRIPTION OF PREFERRED EMBODIMENT As can be seen particularly well in FIG. 1, the sheets 1 produced by a not-shown transverse or cross cutter installation are fed by conveyor belts 2 into the operative zone of the suction brake installation described infra in greater detail, and they then reach conveyor belts 3 after having been braked and overlapped, said conveyor belts 3 depositing sheets 1 on a stack, not shown.

The suction brake installation consists essentially of suction box or chamber 4 which is connected to a not-shown sub-atmospheric pressure producer via pipe extension 5. The upper side or top of suction box or chamber 4 is provided with perforations 6 which are distributed suitably at the same spatial distance over the entire extension of the suction chamber.

At a short distance above the suction the chamber 4, there is provided a perforated cover plate 7 which essentially fills up the intermediate space between conveyor belts 2 and 3. Perforations 8 of cover plate 7 are aligned with perforations 6 of suction chamber 4. Between the upper side or top of suction chamber 4 and the bottom of cover plate 7, there is provided a control belt 9 which is movable in the rhythm of the sheet sequence. In this embodiment, said control belt 9 is constructed as a thin endless belt enclosing suction chamber 4. The size and arrangement of perforations 10 in control belt 9 correspond to perforations 6 and 8 of suction chamber 4 and cover plate 7 respectively.

FIGS. 2 and 3 show that the perforated control belt is guided around drive pulleys 11 which are secured to shafts I2. Followers 13 engage with perforations 10 of control belt 9 and assure a non-slip drive. As the perforated control belt 9 revolves, its perforations I0, as shown in FIGS. 4 and 5, are aligned periodically with the perforations 6 and 8 of suction chamber 4 and cover plate 7 so that there takes place a rhythmic on-suction and braking of the rear end of sheets 1. In this mode, the revolving movement of control belt 9 is controlled in dependency upon the sheet sequence, that is to say upon the advancing speed and the length of the sheets.

Other steps which have been taken permit adjusting the suction output and thus the braking effect exerted upon the sheets to each respective operative condition and the peculiarities of the sheet material, respectively. For this purpose, there is provided a slide member 15 as is shown particularly in FIGS. 2 and 3, said slide member being provided with perforations 14 corresponding to the remaining parts of the suction brake installation. This slide member enables changing of the effective through-flow cross-section of the remaining aligned perforations 6, 8 and 10, as shown in FIG. 6.

In this case also, one utilizes suitably a thin perforated belt which is adjustable transversely to the advance direction of sheets I. At one end of this perforated belt, there engages a draw spring 16 and on its other end a threaded spindle 17 permitting the desired adjustment, see FIG. 7.

In embodiment shown in FIG. 7, there is provided a likewise perforated reciprocating control belt 18 instead of the revolving control belt. The reciprocating movements of said control belt [8 open and close the perforations 6, 8 add 10 of the suction brake installation in the rhythm of the sheet sequence. The reciprocating control belt is driven with the aid of magnets I9 and 20 which are operated alternatively in dependency upon the sheet sequence. Accordingly;

What is claimed is:

1. Apparatus for braking the advance of and effecting overlapping of sheets of paper, cardboard or the like material comprising:

a. means for feeding said sheets in sequence;

b. suction brake means arranged below the path of movement of said sheets for periodically applying suctions acting on the rear ends of successive sheets including:

1. a suction chamber having a perforated top; 2. a cover plate between the top of said suction chamber and the path of movement of said sheets having perforations therein arranged in alignment with the perforations in said top;

3. a perforated movable control belt means arranged between the top of said suction chamber and said cover plate; and

4. means for moving said control belt means lateral to said path of movement and in accordance with the rhythm of the sheet sequence to align the perforations in the control belt means with the perforations in the top of said suction chamber and the perforations in said cover plate.

2. Apparatus as claimed in claim I in which said movable control belt means is a reciprocating perforated belt.

3. Apparatus as claimed in claim I in which said movable control belt means is a reciprocating perforated belt.

4. Apparatus as claimed in claim 1 in which the effective through flow cross-section of the perforations in said suction brake means is adjusted to the speed of said means for feeding blanks.

5. Apparatus as claimed in claim 1 which includes perforated slide means laterally adjustable to said path of movement between said cover plate and said control belt means for adjusting the effective through flow cross-section of the per forations in said suction brake means. 

1. Apparatus for braking the advance of and effecting overlapping of sheets of paper, cardboard or the like material comprising: a. means for feeding said sheets in sequence; b. suction brake means arranged below the path of movement of said sheets for periodically applying suctions acting on the rear ends of successive sheets including:
 1. a suction chamber having a perforated top;
 2. a cover plate between the top of said suction chamber and the path of movement of said sheets having perforations therein arranged in alignment with the perforations in said top;
 3. a perforated movable control belt means arranged between the top of said suction chamber and said cover plate; and
 4. means for moving said control belt means lateral to said path of movement and in accordance with the rhythm of the sheet sequence to align the perforations in the control belt means with the perforations in the top of said suction chamber and the perforations in said cover plate.
 2. a cover plate between the top of said suction chamber and the path of movement of said sheets having perforations therein arranged in alignment with the perforations in said top;
 2. Apparatus as claimed in claim 1 in which said movable control belt means is a reciprocating perforated belt.
 3. Apparatus as claimed in claim 1 in which said movable control belt means is a reciprocating perforated belt.
 3. a perforated movable control belt means arranged between the top of said suction chamber and said cover plate; and
 4. means for moving said control belt means lateral to said path of movement and in accordance with the rhythm of the sheet sequence to align the perforations in the control belt means with the perforations in the top of said suction chamber and the perforations in said cover plate.
 4. Apparatus as claimed in claim 1 in which the effective through flow cross-section of the perforations in said suction brake means is adjusted to the speed of said means for feeding blanks.
 5. Apparatus as claimed in claim 1 which includes perforated slide means laterally adjustable to said path of movement between said cover plate and said control belt means for adjusting the effective through flow cross-section of the perforations in said suction brake means. 